/*
 *  (C) Copyright 2008 Insula T.I. Ltda.
 *
 *  This file is part of Vulcano.
 *
 *  Vulcano is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Vulcano is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with Vulcano.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.openinsula.vulcano.core.command.processor;

import java.util.Iterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.openinsula.vulcano.core.command.Command;
import org.springframework.util.Assert;

public class DefaultCommandChain implements CommandChain {
	
	protected final Log logger = LogFactory.getLog(getClass());

	protected Iterator<CommandProcessor> iterator;
	
	public DefaultCommandChain(Iterator<CommandProcessor> iterator) {
		Assert.notNull(iterator, "CommandProcessor Iterator must not be null");
		this.iterator = iterator;
	}
	
	@Override
	public <T> T doChain(Command<T> command) {
		if (iterator.hasNext()) {
			if (logger.isDebugEnabled()) {
				logger.debug("Getting next CommandProcessor to process Command.");
			}

			return iterator.next().doExecute(command, this);
		} else {
			if (logger.isDebugEnabled()) {
				logger.debug("Reached end of CommandChain. Executing Command.");
			}
			
			return command.execute();
		}
	}

}